Estimation of formation properties based on fluid flowback measurements

Abstract

An apparatus for estimating properties of an earth formation includes a carrier connected to a drilling assembly, and a sensor assembly configured to measure at least one return flow parameter of a return fluid at a surface location, the return fluid returning to the surface location from a borehole. The apparatus also includes a processor configured to perform receiving one or more return flow parameter values for a period of time after injection of fluid is stopped, analyzing the one or more return flow parameter values to identify a ballooning event, in response to identifying the ballooning event, estimating at least one of a location and a property of one or more fractures in the formation, and performing one or more aspects of at least one of the drilling operation and a subsequent operation based on at least one of the location and the property of one or more fractures.

What is claimed is: 
     
       1. An apparatus for estimating properties of an earth formation, the apparatus comprising:
 a carrier configured to be deployed in a borehole in the earth formation, the carrier connected to a drilling assembly configured to perform a drilling operation that includes including injection of fluid into a borehole; 
 a sensor assembly configured to measure at least one return flow parameter of a return fluid at a surface location, the return fluid returning to the surface location from the borehole, wherein the sensor assembly measures the at least one return flow parameter of flowback coming out of the borehole after pumps of the drilling operation have stopped; and 
 a processor configured to perform: 
 receiving one or more return flow parameter values of the flowback for a period of time after injection of fluid is stopped; 
 analyzing the one or more return flow parameter values to identify a ballooning event; 
 in response to identifying the ballooning event, estimating at least one of a location and a property of one or more fractures in the formation; and 
 performing one or more aspects of at least one of the drilling operation and a subsequent operation based on at least one of the location and the property of one or more fractures, 
 wherein the processor is configured to receive one or more return flow parameter values for each of a plurality of periods of time and estimate a return flow parameter magnitude for each period of time, each period of time associated with a different borehole depth interval, and analyzing includes comparing a magnitude of the one or more return flow parameter values for the period of time to the return flow parameter magnitude associated with one or more other periods of time, and 
 wherein analyzing includes estimating at least one of a ratio and a difference of the magnitude of the one or more return flow parameter values to a reference value, and identifying the ballooning event based on the ratio and/or the difference being equal to or greater than a selected threshold. 
 
     
     
       2. The apparatus of  claim 1 , wherein the at least one return flow parameter includes at least one of flow rate, return flow volume and volume of fluid in a fluid source. 
     
     
       3. The apparatus of  claim 1 , wherein the processor is configured to compare a magnitude of the one or more return flow parameter values to a selected threshold, identify the ballooning event based on the magnitude being equal to or greater than the selected threshold, and estimating at least one of a size and an extent of the one or more fractures based on the magnitude of the one or more return flow parameters. 
     
     
       4. The apparatus of  claim 1 , wherein analyzing includes determining a pattern of the one or more return flow parameter values, and comparing the pattern to a selected pattern associated with the ballooning event. 
     
     
       5. The apparatus of  claim 1 , wherein performing the one or more aspects includes evaluating parameters of the drilling operation during drilling, the parameters including at least one of the size and type of materials circulated into the borehole, evaluating productive zones in the formation during drilling, and monitoring borehole integrity during drilling. 
     
     
       6. The apparatus of  claim 1 , wherein performing the one or more aspects includes at least one of monitoring and adjusting managed pressure drilling (MPD) parameters during the drilling operation. 
     
     
       7. The apparatus of  claim 1 , wherein analyzing includes estimating at least one of a size and an extent of the one or more fractures based on the ratio and/or the difference. 
     
     
       8. The apparatus of  claim 1 , wherein analyzing includes generating a composite return flow parameter including a plurality of different return flow parameters, and identifying the ballooning event based on the composite return flow parameter. 
     
     
       9. A method of estimating properties of an earth formation, the method comprising:
 deploying a carrier in a borehole in the earth formation, and performing a drilling operation that includes injection of fluid into a borehole; 
 measuring at least one return flow parameter of a return fluid at a surface location for a period of time after injection of fluid is stopped, the return fluid returning to the surface location from the borehole, wherein the at least one return flow parameter is a parameter of flowback coming out of the borehole after pumps of the drilling operation have stopped; 
 receiving one or more return flow parameter values of the flowback at a processor, and analyzing the one or more return flow parameter values to identify a ballooning event; 
 in response to identifying the ballooning event, estimating at least one of a location and a property of one or more fractures in the formation; and 
 performing one or more aspects of at least one of the drilling operation and a subsequent operation based on at least one of the location and the property of one or more fractures. 
 
     
     
       10. The method of  claim 9 , wherein the at least one return flow parameter includes at least one of a flow rate, a return flow volume and a volume of fluid in a fluid source. 
     
     
       11. The method of  claim 9 , wherein analyzing includes comparing a magnitude of the one or more return flow parameter values to a selected threshold, and identifying the ballooning event based on the magnitude being equal to or greater than the selected threshold. 
     
     
       12. The method of  claim 11 , further comprising estimating at least one of a size and an extent of the one or more fractures based on the magnitude of the one or more return flow parameters. 
     
     
       13. The method of  claim 9 , wherein analyzing includes determining a pattern of the one or more return flow parameter values, and comparing the pattern to a selected pattern associated with the ballooning event. 
     
     
       14. The method of  claim 9 , wherein the processor is configured to receive one or more return flow parameter values for each of a plurality of periods of time, and analyzing includes estimating a return flow parameter magnitude for each period of time, each period of time associated with a different borehole depth interval. 
     
     
       15. The method of  claim 14 , wherein analyzing includes comparing a magnitude of the one or more return flow parameter values for the period of time to the return flow parameter magnitude associated with one or more other periods of time. 
     
     
       16. The method of  claim 15 , wherein analyzing includes estimating a ratio of the magnitude of the one or more return flow parameter values to a reference value, and identifying the ballooning event based on the ratio being equal to or greater than a selected threshold. 
     
     
       17. The method of  claim 16 , wherein analyzing includes estimating at least one of a size and an extent of the one or more fractures based on the ratio. 
     
     
       18. The method of  claim 9 , wherein analyzing includes generating a composite return flow parameter including a plurality of different return flow parameters, and identifying the ballooning event based on the composite return flow parameter.